The present invention relates to semiconducting devices, and more specifically, to methods and systems for determining doping type and level in individual semiconducting nano structures.
A nanowire is a nanostructure, which can have a diameter on the order of nanometers. Nanowires exhibit various quantum mechanical properties due to the quantum confinement resulting from the diameter of the nanowire. As such, nanowires can be implemented in many technologies including but not limited to electronic, opto-electronic and nanoelectromechanical devices, as additives in advanced composites, for metallic interconnects in nanoscale quantum devices, as field-emitters and as leads for biomolecular nanosensors. In order to control the quantum mechanical (and other electrical) properties, the nanowires can be doped by various techniques, including diffusion and implantation. While doping techniques can in theory result in a known doping level, the dopants do not always incorporate into the nanowire structure. Electrical measurements can be made on the nanowire to determine electrical properties of the nanowire. However, while electrical measurements can be made on individual nanowires, extracting doping levels can be problematic due to contact issues. Doping levels are one of the technological pieces of information necessary to the formation and proper performance of a device such as a digital switch or sensor, in which the nanowire is implemented. In addition, doping level is an enabler to making a nanoscale device operate as, for example, a field effect transistor. As discussed above, accurate, controllable doping in nanostructures is, in itself difficult to achieve. As a result it is necessary to be able to measure the doping levels of nanostructures in both the development and eventual manufacturing stages.